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CHROMIUM PLATING REPLACEMENT AT

SIKORSKY AIRCRAFTROBERT GUILLEMETTE

JOHN BARTALOTTA

MATERIALS AND PROCESSES ENGINEERING

APRIL 26, 2001

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OUTLINE

• I. Current chrome plating applications

• II. Past & current efforts with thermal spray coatings

• III. Methodology for qualification of thermal spray coated components

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US ARMY US NAVY

US AIR FORCE US MARINES

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Current Applications for Chromium Plate

• Airframe

• Drive System

• Rotors

• Flight Controls

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H-60 Airframe Chromium Plate Replacement

AXLE

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H-60 Drive System Chromium Plate Replacement

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H-60 Main Gearbox Chromium Plate Replacement

SEAL SLEEVE, MAIN ROTOR SHAFT

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H-60 Intermediate Gearbox Chromium Plate Replacement

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H-60 Tail Gear Box Chromium Plate Replacement

INBOARD RETENTION PLATE SLEEVE

OUTPUT GEAR

TORQUE WASHER

INPUT

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H-60 Main Rotor Head Chromium Plate Replacement

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Flight Controls Chromium Plate Replacement: non-hydraulic and hydraulic components

Boost Servos

Primary Servos

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Base Metals Plated With Chromium

• Steels– 4340 (150-280 ksi)

– 300M (280 ksi)

• Stainless Steels– 17-4

– 15-5

– PH13-8Mo

• Aluminum– 7075-T73

• Titanium– None

• Carburized Steels– None

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PRIMARY ALTERNATIVES

DETONATION GUN

SUPER DETONATION GUN

PLASMA

HVOF

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Detonation Gun

• Over 35 years experience with detonation gun thermal spray coating

• Excellent track record

• Specified for difficult, critical applications

• Chromium replacement primarily done for improved performance, now environmental driven

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Current Super DGun Technology

• Several applications on S-92 and RAH-66 Comanche

• Implemented reduced weight designs by taking advantage of improved fatigue strength of DGun over chromium electroplate

• Comparison testing shows Super DGun has superior fatigue properties to HVOF

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HVOF Coating Evaluated at Sikorsky Aircraft

• Diamond Jet– Aluminum Silicon– tungsten carbide

• JP5000 Tungsten Carbide

• Jet Kote tungsten carbide

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Base metals coated with thermal spray coatings

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Detonation Gun Tungsten Carbide reduces fretting fatigue at bearing journals (implemented 1987)

Thermal Spray Tungsten Carbide Results in Substantial (6x) Life Improvement for H-60 Main Rotor Shaft

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HVOF Aluminum Silicon for Rework of Magnesium Transmission Housings (implemented 1992)

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SH-60 DAMPER

•IMPROVEMENTS

– ZERO LEAKAGE FROM THE STATIC SEAL AREA HAS BEEN ACHIEVED SINCE THE INCORPORATION OF THE TUNGSTEN CARBIDE COATING.

– THE TRIBALOY AND TUNGSTEN CARBIDE COATINGS ARE SHOWING A GREAT IMPROVEMENT OVER THE CHROME AT 750 HOURS.

•ISSUES

– DAMPER BENCH TEST STOPPED AT ~750 HOURS DUE TO LEAKAGE FROM DYNAMIC END OF DAMPER AND FAILURE OF THE NON-METALLIC BUSHING.

– AWAITING STRONGER NON-METALLIC BUSHING FROM SUPPLIER. THE BUSHINGS ARE EXPECTED TO BE DELIVERED LATE MARCH 2001.

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Tail Landing Gear Piston

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SH-60B Tail Landing Gear Piston, Cleveland Pneumatic PN 2012C4, Base Metal: 300M Steel, Coated with SDG2057 tungsten carbide chromium

Qualification Test matrix for Navy H-60 Tail Gear Piston

• Coating adhesion• Tensile• Fatigue (HCF)• Fatigue (LCF)• Cyclic stress/strain• Metallurgical• Wear test (bench

scale)

• Drop test (full scale)• Corrosion

– open section

– crevice testing

• First article destructive evaluation/validation

• NAVAIR review• Lead-the-fleet testing

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UH-60 Tail Landing Gear Fork

UH-60 TAIL LANDING GEAR

Fork

Qualification Test Matrix for UH-60 tail landing gear fork

• Adhesion (coupon)• Metallurgical (coupon &

full scale)– hardness– porosity/uniformity– heat/mechanical effect on

substrate

• Fatigue (coupon)• Fatigue after exposure to

salt fog (coupon)

• Wear test (data from Garlock)

• Corrosion testing (full scale)

• Army AMCOM review

• Lead-the-fleet testing

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Guidelines for qualification of components with chrome plate

replacement• Parts have frozen process planning. Change of supplier

may require full scale testing• Difficulty exist with across-the-board substitution by

similarity qualification• Lead-the-fleet (actual service operations) often needed

as part of qualification• Flight Safety parts to be addressed by Flight Safety

Change Board

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CONCLUSION

• Chromium replacement for multi-service helicopters is a continuing effort at Sikorsky Aircraft

• Criteria for qualification is a major challenge